While your critiques about the historical context these texts came from are valid, I don't think it's for you to say categorically that there is "no wisdom" in ancient teachings like the Kama Sutra whatsoever. Especially when you're judging them based on English translations and you don't come from that culture. Could it be that people who have more education in reading Sanskrit would be able to interpret actual spirituality from the Kama Sutra? It could be that the translation you read gave a misleading perspective, because one thing I do know about Sanskrit (while I'm not an expert) is that every word means about 20 different things simultaneously. So every phrase in Sanskrit has multiple meanings that usually have some kind of surface level meaning as well as deeper philosophical and spiritual meanings.